Neuroimaging has become the central method for the analysis of human brain function. It holds promise of clarifying systems-level pathophysiology of mental disorders, and transforming their diagnosis and treatment. "Seeing" the brain in action is itself a powerful motivator for students and professionals. At the New York Hospital-Cornell Medical Center we have developed two laboratories concerned with imaging both adults (Functional Neuroimaging Laboratory) and children (Sackler Institute). We propose to develop a national training center for clinical investigators in Cognitive Neuropsychiatric imaging. By clinical, we mean to include disorders of the central nervous system of the type commonly considered psychiatric, including schizophrenia and depression, as well as those more commonly called developmental such as autism, attention deficit hyperactivity disorder and learning disabilities. By neuroimaging we mean to include hemodynamic methods such as PET and fMRI as well as electrical recording from inside or outside the brain. We plan both to train professional clinical researchers in psychiatry, psychology and related fields, and to develop and test materials here at Cornell Medical Center that may be used in medical school, psychiatry and psychology departments, and in pediatric programs in the U S. and abroad.